Vibratory reed electronic musical instrument



March 23, 1954 Filed Oct. 15, 1951 B. F. MIESSNER 2,672,781 VIBRATORYREED ELECTRONIC MUSICAL INSTRUMENT 3 Sheets-Sheet l LLI CD D d E 1 11111 111 Y 111 1111 11111 IX PARTIAL N03 RELAT|VE 1 2 3 4 5 6 7 8 9FREQUENCY' 4 A FIG? AMPLITUDE ACTUAL OUND IDEALIVZED SOUND BOARD nua uwm/0 20301050 /00 300 .500 I000 amo w c FREQUENCY IN CYCLES PER SECOND OFTHE VIBRATORS (STRINGS) INVENTOR ATTOR EY March 23, 1954 B, WESSNER2,672,781

VIBRATORY REED ELECTRONIC MUSICAL INSTRUMENT Filed Oct. 15, 1951 I 5Sheets-Sheet 2 Z8, m, 2.2 m, m, 26, /a

5 FIG. 6

SPEAKER TRANSLATOR AMPLIFIER J Jj L,

INVENTOR BENJAMIN E MIESSNER ATTO March 23, 1954 F; MESSNER 2,672,781

VIBRATORY REED ELECTRONIC MUSICAL INSTRUMENT Filed Oct. 15, 1951 3Sheets-Sheet 3 64 FIG. /0

INVENTOR BENJAMIN F. MI ESSN ER ATTO NEY Patented Mar. 23, .1954

VIBRATORY REED ELECTRONIC MUSICAL INSTRUMENT Benjamin F. Miessner,Harding Township, Morris County, N. J., assignor to Miessner InventionsInc., Harding Township, Morris County, N. J

a corporation of New Jersey Application October 15, 1951, Serial No.251,363

11 Claims. (c1. s4- 1.15)

2 This invention relates to electronic musical instruments utilizingclamped-free vibratory reeds as tone generators and more particularly toa novel arrangement of the translating devices associated with suchreeds for the production of 5 desired tonal effects.

The complexion of the output tones of a tensioned-string piano ismarkedly affected by the natural frequency and energy-dampingcharacteristics of the piano soundboard which effects are known asformant action or as formant efi'ects. These generally occur within asingle cycle of vibration but may extend over a number of completecycles before extinction by more or less string damping influences, inwhich case they are more properly classed as broad-band resonanteffects. Both kinds are present in piano Soundboards but they will bereferred to herein as formant efiects because of their tone qualityforming action. In essence, this formant action generators and theintroduction of the formant effect into the audible tones of suchinstruments must be accomplished without a soundboard as such.

An object of this invention is the provision of means for producingconventional soundboard effects in an electronic musical instrumentutiliz- 1ing beam type vibrators as tone generators.

An object of this invention is the provision of a novel mountingarrangement for translating means associated with vibratory reed tonegenerators.

An object of this invention is the provision of novel and improved meansfor coupling vibratory reeds, in an electronic piano employing suchreeds as tone generators, to provide improved output tones throughout awide pitch range.

An object of this invention is the provision of means for producingformant effects in an elecerably, no direct sound radiation of thetoneinvolves thegeneration of broad bands of vibration frequenciesvarying in mean or average value from one end of the piano bridge systemto the other. Such vibration frequencies arise both by hammer impactaction on the tensioned strings and by forced and resonant action andreaction between the strings and the bridge-soundboard structure. If,for example, a C key for a 130.8 cycle per second, lower register stringbe struck and the bridge-soundboard structure in the region of suchstring has a broad frequency response spanning 130.8 C. P. S., thebridge-soundboard structure will readily accept the 130.8 C. P. S.vibration partial I of the string. In fact, the structure willalsoaccept the higher numbered, integrally-related vibration partials of thestring and will radiate all such vibration frequencies as long as thestring continues to vibrate. Forth'ose vibration frequencies of thesoundboard having the strongest coupling, together with efiicientradiation or other damping losses for strings having a group of partialswithin the soundboards strongly coupled band of frequencies, thosestring partials within this band will be relatively more rapidly dampedthan other partials of the string. Also, for these frequencies thebridge-soundboard structure will react back on the string to influencestring vibration, in the manner of all coupled, resonant vibrators,mechanical or electrical. The net acoustical effect of the formantaction is to make those vibration partials which are rapidly transferredto the soundboard of strong, initial amplitudeand shorter timeconstant.

In electronic musical instruments there is, preftronic piano employingvibratory reeds as tone generators together with means for selectivelyproduce output tones of varying such effects to desired character. 26

\ predetermined manner.

An object of this invention acoustic means.

These and other objects and advantages of the invention will be apparentfrom the following description when taken with the accompanying It willbe understood the drawings are forpurposes of illustration and are notto be condefining the scope, or limits of the invention, reference beinghad 'forthe latter purpose drawings.

strued as to the appended claims.

An object of'this invention is the provision of a tone-producingassembly for an electronic musical instrument said assembly comprising areeds secured to a .reed rail, vibration-translating pick-ups associatedwith the reeds, pick-up supporting means secured to the reed rail, avibratile support for the and electro-magnetic means for vibrating thevibratile support in a is the provision of a tone-producingv assemblyfor an electronic musical instrument and comprising a series ofvibratory reeds and associated pick-ups mechanically coupled to a commonreed rail, a rigid base, resilient members disposed between the reedrail and the base, mechanico-electro-acoustic means for translating reedvibrations into sound, electromagnetic means for vibratingthe reed rail,and an electrical feedback circuit connected between theelectro-magnetic means and the electro- In the drawings wherein likereference characters denote like parts in the several views:

Figure 1 is a curve illustrating the relative amplitudes of thevibration partials of a tensioned string mounted on a massive,non-vibratile support;

Figure isipa curve :simwingstheavariationof; the amplitude of asoundboard (of a high quality, large-size, grand piano) related to thevibration frequency of the immediately proximate; tensioned string; 1-

Figure 3 is a fragmentary, top plan view of a reed and pick-up assemblymade in accordance with my invention; 7

Figure 4 is a front elevationrnf the assembly shown in Figure 3;

Figure 5 is a cross-sectional view taken along the line A--A of Figure3; w i

Figure 6 is a side view of in Figure 5 and including adiagrammaticshowing of my arrangement 'for vibrating the reedpick -upassembly to provide" desired formant eflects;

Figure flis similar toFigure'fi, with the-elec trical componentsomitted, and s'howing: a modi flcation of the invention wherein th platesup-- porting the pick-ups is madec of non magnetic material;

Figure 8 is a plan view similar to Figurew3, and showing anotherconstruction of the pick-ups and their supporting posts;

Figure 9 'is a' longitudinal, cross-sectional view taken along the lineA-A' of Figure 8; and

Figure 10 is a cross-sectional view similar to. that-of Figure 9, andshowing-a2 single pickup and. supporting: post' of anothericonstruction, drawn to an enlarged scale;

As is well, known, the initial: amplitudes of the r vibration partialsof a tensione'd string mounted r on alrigidbase, are not-equal'but,:rather, decrease T substantially; :uniiormyly as tha partialnumber-increases; Figured. lillustratessth'e relativevibration-amplitudes". ofcthe first mne vibra-r tion partials not 1atensioned. stringnit iceingznoted that the partials are integrallyrelated and' that the partials higherthampartialrIVlhave amamplitudeiess than'one-half that of the ifundamental partialaL The:decrease: in;v amplitude from. one ,to the nextghigher martialiswdetermined chiefly by the r characteristics r :of ithe string', thesoftness andlength of thevstriking hammeralong the string, and thespecific point on :the string, where the hammer strikes, However, anyone of I 1 these partials mayibe entirely, absent, or-of ab: normallylower amplitude, ,dueto the dampin action ,ofthe exciter, hammer duringactual impact'with' the string, .yIna piano, the striking point, alongthe string, is sochosen that the Partial VI'I'is so "eliminated,crdamped. out:

' As "stated above the bridge-soundboard *structure'ofapiandhasabroad-bandirequency characteristicwhich" varies throughout *the scaleof strings-from the lowerend of the bass bridge to the upper-endofthe-'treblebrid'ge; "Many fac tors in-fiuence this frequencycharacteristic from point "to point along-the scale suchaspthe"distribution of the thickness; mass and iongitudinal stifiness of thebridge, the bearing"-pressure-of' the -tensioned-strings upon-thebridge, theproxthe assembly. shown ing rate'ofthe soundboard varies withhumidity.

4 board for diiferent frequencies along its length from bass to trebleends, etc. Since the soundboard is, in effect, an upwardly and convexlyarched membrane of irregular shape and variably loaded by the bridge,and since it is pressed wa d bathe pressure .of,a1i the,,strings intoram equilibrium p'psition aagainstg, its own upwardly acting compliance,its natural vibration frequency varies along the entir bridge in amannerthat is difiicuit to calculate or, in fact, vclui'rlicaterin"arrygvgirennumber of instruments.

pPiams made by the same manufacturer and which appear, outwardly, quiteidentical in design and-*cmistructicn-will sound differently in "1 .i.01 gch'ief, interest; here the. same .nitehiranges.

is the fact that the soundboard frequency and damping character-,yistics mavkedly .aflect the complexion of the out- Duttones by formantaction, and this tonal complexion varies, or shifts along the pitchscale of every such instrument-in a way which is detel-mined chiefly bythese formant effects; In addition- 'to the net overa1l difference inthe J formant effect as 'establishedbythe initial physical relationshipsof the coupled parts; the damp- For example, a piano with a soundboardhaving little or no -moisture content will sound bright and crispLWith-.-continued exposure to highhumidity atmosphere the soundboard willabsorb moisture and its it natural vibration frequencies" will-be-lowered due to -the-added loading effect of this water content and therise in its; internal vibrational 'resistanca whereby the output-toneswill have a- -higher damping rate and tvill sound dull and lifeless.

-Intests made ona small'grand -piano Ihave found that r the' naturalvibration frequencies *of the soundboard varied smoothly from 90 to 550cycles persecond; between the two-extreme ends +2. of "the bass andtreble bridges. In the larger grand pianos the: drequency'range has"alarger spread and theatrequency variation is more uniformovemthascalemangm (Figure 2 is a curv showing the vibration amplitudeof. a soundboard, at positions immediate- 1ybeiowtstrings having:theindicated fundamentalrfrequencies, or a -largest size grand plane ofEuropeans.i'i'ianufacturei Superimposed -on such curve is a' similarcurve-of anideal soundboard.- Ideally; ofrcourse; the soundboard shouldhave a response frequency close to that of the adjacent strings .andsuchcurve should be smooth; start ing at about 30 cyclesrper second andendlng at" 4,000 to-5,000 cyclesper -second. Then thecorwouldbedepressedain amplitude. However; the;

vibration partial II n'fsuch-string. has a frequency 1 of 1,000 C. P. S;falling 'atithe relatively highpoint Ben the curve and, cons equent1y,thisvibration imity of "the bridge to--thefixed edges off thepartia1' iselevatedprelatively, lintoutput sound amplitude. .,Anotherstring.having,a fundamensoundboardy'the thickn'es'sgofthe soundboard and:

constants' oifithe: materialior LWIi'ic ifihese w rts;

tai,vibrationjrequencyof $50G. ,P. wouldhaye. a relatively, elevatedamplitudefonpertial 1' (fa l ing at the point C)' while its partial IIof: 900;,;,- are *made, 'the radiationempiencyzofithe sound-f JMCPR,vouldheneprassed (iauing. ,at- .the no1nt rectmimpedanceematching foruniform energy transfer: from the strings f to the soundboardwould"obtain- =and =there would "be no "regions of the: scale-where thetonequal-ity would b markexample; ii" a bridge-coupled D). Since thequality of a piano tone changes as the string vibration amplitude fallsoff, the first example tone, having its partial l1 damped out at a rategreater than partial I, will have a noticeably different quality thanthe second example tone subject to the reverse damping effect.

Sinc soundboards are strongly damped mechanico-acoustic transducers,their vibrations do not continue much beyond the time confines of a fewcycles of string vibration and their action is very closely similar tothat of the formant effects in the mouth, nasal passages, larynx, etc.of the human voice apparatus. These members, in different individuals,produce different tone qualities at the sam pitches due to the stronglydamped but intra-oyclic resonant actions of these coupled resonatorsdriven by the air puffs released by the vocal chords. In windinstruments, the formant action is varied from one instrument to anotherchiefly by the shape of the air column confined more or less within theboundaries of the instrument. In soundboard instruments employing thesame kind of strings the formant action and output tone quality isvaried from one to anotherchiefly by the soundboard design as tofrequency and damping characteristics.

In electronic musical instruments having no soundboard, such asinstruments employing vibratory reeds for tone generators, the formanteffects must be provided by an added element whose vibration is inducedby output of the tone generators and such induced vibrations isreintroduced into the translating system.

In order to provide formant effects, in a vibratory reed type ofelectronic musical instrument, simulating those of conventional instruments, the vibrational characteristics of the formant-producing systemmust correspond to those of the particular instrument being duplicated.Since the frequency damping characteristics of soundboard instrumentsare not yet entirely known and since their damping characteristics arevery difficult to measure by reason of their high absolute values, theduplication, in an electronic instrument, of a particular conventionalinstrument must be accomplished by cut and try methods. When, however,the formant-' producing system to be added to an electronic instrumentis provided with variable frequency and damping controls along the scaleof the tone generators the effects maybe adjusted independent- 1y, untilthe listening ear accepts the electronically produced tone as comparableto the tone of a conventional instrument.

In carrying out my invention, as applied to a clamped-free reed type ofelectronic piano, I provide. a vibratile support for thereed-vibrationtranslating pick-ups which supportis attached to thereed-mounting rail in such manner that. the reeds, when vibrating, tendto vibrate the pick-up support whereby the translating system willtranslate the combined vibrations of the reeds and of the pick-upsrelative to one another.

Reference is now made to Figures 3, 4 and 5, Figure 3 being afragmentary top plan view of one novel mounting arrangement for thepickups, Figure 4 being a front elevation thereof, and Figure 5 being across-sectional view taken along the line AA of Figure 3. Th vibratoryreeds I I), I I I2, are clamped to the rail I3 by suitable, hardened setscrews I4; I5, I 6, each such set screw being alined with a cooperatingsimilar screw such as the screw I5 shown in the crosssectional view ofFigure 5. The'reed rail I3 is v provided with transverse holes I1,l8,-'" l9 afford ing unrestricted vibration ofv the individual reeds.This particular reed-clamping arrangement offers numerous, practicaladvantages. Each reed is adapted for excitation, percussively orotherwise, by any suitable means and will vibrate in the directionindicated by the arrows a-a in Figures 4 and 5. Thevibration-translating pickups, here shown as the capacitive type,comprise the individual metallic plates 20 to 21, inclusive, each platebeing secured to the associated post to 31 as by the screws 28, suchposts being made of suitable insulating material such as a plastic. Itmay here be pointed out that the posts are internally threaded to acceptthe fastening screws 28 and each of the pick-up plates is provided withan oversize hole whereby the spacing of the plate relative to theadjacent side of the reed may set to a predetermined value before thefastening screw is tightened. Further, if the plane of one or more of,the pick-ups is to be altered with respect to the plane of theassociated reed, when the latter is in the at rest position, this can bedone by driving the insulator posts in one or the other direction in theholes provided in the metallic plate 40. made slightly undersizedrelative to the outside diameter of the posts whereby the posts will beself-supporting when driven into such holes. Alternatively, the plane ofeach individual pick-up can be altered by placing shims between thepick-* up and the top of the supporting post. Each pair of pick-ups isso positioned that the transverse axis thereof coincides with nodalpoint for the vibration partial II of the intervening reed. Thus, whenthe reed is excited by percussive means, such second vibration partial,which is dissonant relative to the reeds partial I, is eliminated fromthe translating system.. The plate 49, preferably made of steel, issecured to the lower surface of the reed rail I3, by screws locatedbetween the reed-clamping screws, and is spaced from the plane of thereeds a distance suilicient to permit maximum amplitude of reedvibration. It will beapparent the pick-ups are electrically insulatedfrom the reeds andthat all reeds can be connected into .an electroniccircuit by means of a single lead. attached to any part of the reed baseI 3 or plate 4i}, and that the pick-ups all can be connected by means ofa lead secured to the ends of the fastening screws 28. Those skilled inthis art will know the reeds and pick-ups form part of a radio-frequencycircuit in which the oscillation frequency or amplitude is affected bythe capacity between the reeds and the pick-ups and such frequency oramplitude will be modulated by the change in capacity brought about byvibration of one or more of the reeds relative to their associatedpick-ups or of the pick-ups relative to the reeds. Such modulations aresuitably amplified, demodulated, etc. to operate a loud speakerproducing audible tones.

In order to superimpose desired formant eifects into the audible outputtones of the instrument I mount the assembly, shown in Figures 3-5, on arelatively'thick, non-vibratil base and provide electro-magnetic meanrfor vibrating the assembly in a specific manner by feedback energyderived from the electrical output circuit of the pick-up system.

9 Reference is now made to Figure 6 which shows the assembly of Figure.5, comprising the reed rail I3, reeds II, pick-upsi24 and thesupporting plat 40, secured to :the side of a thick n'onvibratile basebymeansof screws 46, washers 48. The'screws 46 pass through holes 46',see

The holes in the plate 40 are amvem amplitude lrelativeito that of thestruck reed) 01 the platedmto ward andaway from "the reed; as: shown by:the? arrowsrc; c. Vibration of: the reed base: I 8'; iandioirl'theplateif W, :is reslsted by the compliance ot-ftne "bend in thezplatc 40,the com-'- pression'randzcompiiance niithe pad' fli as-well bysi'itsrinternal viscosity ror vibrational resistano(=.-': Insamusicalseriesi'or tunedii reeds- -the length of the? individual"reed'siwillivary; generailvtfrom' a maximumnini the lowfre'quency'orbass section I to e: m'inimum'i in" the high -frequencyprtreble increased whiteuortne'pomtsn to mandate G'i" thei'energwiossesmusthe decreased."-

Iriia' tensioned string: piano, each string has a series very nearlyintegrally-related fie quen'cy partials whereas. a clamped -free reedhasno such fortunate partlal frequencyrelationship;

The relationsliipof such partial frequencies to the fundamentalfrequency (partial 1) is as follows:

Freq. ofPartial to Fundamental rciamp'ed- L String section; Since it? isdesirable to position each paiflofi'pickx-ups atathers-nodal point ofvibrationpartial llxfort'the"interveningt reed, it is-apparent"therwidth ofdthepick up supporting: plate 40 will i varyfixilikezmanrier: I prefer to makethe width" of r the' plate". 40 2 about 80of the length. of the innnediately above-disposed reed so that suchplatex width z'will also' be a:vmaximum at the low' frequencyreeds-position and a minimum at the high: frequency? reedz position. Thethickness of the plate andthe elasticity :of Y the material ofwhichrthnrplate is made are 1 so "chosen" that the plate s segmental:vibration period *is about equal to thefundamental frequencies of theimmediate- 1y proximatetreedsi The-plate thickness for any 35 glverrpointi m'ay be found by forming such" a plate i'segmentzequal tothecentr-to-cehter spacingf of the'reedsy attaching-thereto a pair "ofsup-'- port p0sts, iplck-ups and fastening screws to rep-- resenttheieactualllplateiloa'd, clamping such arrangement in" a vice,vibrating the free end (ca-rryingthe picis-ups) land-actually measuringthevibration frequency: The plate -Ml preferably is made of steel, forpurposes to" be 'explainedhereinbelow," ami itscorrect thickness is thatwhich will give a frequency" response equal to that of the-moximatereed," with due consideration being given;to' -suclrliifaietors asathe':loading 1 provided by the :"pick ups and; their supporting structure. Ifnecessary; holes may'be drilledthrough'the plate to raise thenaturalvibrationi frequency *above "its normal value;- orloading-membersoflead brother material "maybe as specific points=tolower thewnaturai frequency; alltfo'r th'e purpose-of-pro-- ducing' a'particular and varying frequency chars acteristic: 1 -along' thep1atelength; thatfis', the dlmensionIin the longitudinal direction orthe rail? la; 1 havezifoundi that'iforireeds havingwa thick nessrroi0.032 winch; the: plate lil may be' =made-"of inchthiclc steel, in orderto have the approxi mately correct frequency response alongthe scale" ofreeds.

sincerithe damping" characteristics of an actual piano' soundboard; asshown bythecurve 'of Fi 1 ure 12 also varyi'alongItheapianobridgeathisfac tor imust'iialsolbe:rsiriiulatediintmy vibration= simu-= latingfipick 'up'support' 'lil Forthls-upurposetthe width, :thicknessprviscosity' of thelpad 41 maybe varied, along the length of theplate-"MT; these means the desired variation of: damping may; beobtained as distinguished from 5am other wisesmooth-curve such'astheeurve ofwtheidealizedt soundboard shown-- Fomsuchihigh-dampingmeal-chaosittieipointsm aad n'om? the curve thadainpingorenergy lowes -mush When a? tensionedstrinsof a piano vibrates" with"varying pressure on an associated soundboard's hirldge each and all ofits many and closelyespaced' vibration partials produce theirowniiv'rbrating forceson the soundboard; -Also,

other neighboring and further distant Striiig-s havingrfone or?more-partial frequencies equal to one' or' more-partialsr of" th'eexcited string; and' having more or less-coupling to it; will respondbyiresonant vibration producing a complextone:

Also; thehhammer impact on the string is transmittedr to: the 1soundboard producing a wide: and

continuous band of irequencies' resulting in the characteristic thump orrap."" In the* case of a: clamped-free reed" the vibration partialsareim'uch further':'separated; frequency w is'e; and suoh partialsareficompletely inharmonic; Thus,

the nearest reed; in'a musical scale series of tuned reeds; havinge--near resonant vibration compo nent; equal' 'in frquencyto partial I ofi an excited reed will beereinoved liva frequency spread of 6.27: times'the fundamental frequency of the struck read; 1 Such frequency spreadcorresponds to about "2 /2 octaves above the struck reed 'or' adistanc'e equal 'to about 30' reeds along thereed ram 'riiis'compareawitn a spacing-of'about'lz strings in a" conventional piano.Consequently. the coupling irra 'tehsioned string piano is tighterthaniri an electronic piano utilizing clamped free vibratory reedslAlso, as alreadystated' partial" II of a vibratory reed 'is dissonantwith partial I. Therefore, the partial vibrations of a reed flndvery'few, if any, resonant'partials, in a series of tuned reeds, toaugment the transits-ml reed" vibrations; factors, theassemblvendarrangement thus far tru'e tonal eifectsbcorresponding' to those --of agiven conventional musical instrument 'such" as, for'example: the piano.I'overcomesuch defij ciencyvbvintrcducing' into thevibratile pick-upsupport f many *integrally related vibration parmental: form,lam-adjustable polarizedcore' 50 surrounded by'a coili-h The =coil-issecured in fixed position within an. appropriate "aperture-in thebasa 45am suitable means and the core Sm-ma be-threadedQto operaterwithimthein: sulator tuberfl which;thacoilzisawound" 1 Sevenelmfo'suoh coilsandecolte'r assemblienare :z' 'spaeedmt intervals talcum i the;longitudinatridh Because of these;

mension of the plate 40 and at different distances from the pick-upsupports 34, as required.

the pick-ups and vibrating reeds are converted into correspondingelectrical waves which are demodulated, amplified and fed to the speakervoice coil. As disclosed in my copending United States patentapplication Serial No. 169,714, filed June 22, 1950, the pick-ups can besopositioned relative to the coacting reeds that the wave form of theamplifier output current will include a full series of Fourier seriespartials 1, 2, 3, 4, 5, 6, etc., times the fundamental vibrationfrequency of any one or more vibrating reeds. Such wave forms are fed tothe coils 56 resulting in a vibration of the plate 40 (and the attachedmembers comprising the reed rail, reeds, and pick-ups) in a mannercorresponding to the normal frequency partials of the strings in aconventional piano. The phase of the feedback current may be made aidingor opposing, as referred to the partial I of the vibrating reeds, and ofdesired amplitude, by adjustment of the slider S on the potentiometer53. Such adjustments will depend upon whether more or less amplitude ofpartial I is desired in the output tones of the loud speaker. It willalso be apparent the magnitude of the feedback current can be made stillfurther controllable, as by a separate amplifier and controls fed fromthe speaker amplifier. When the reeds and pick-ups are so vibrated,through the medium of the plate 46, a corresponding relative vibrationoccurs between the reeds and the pick-ups which vibrations aresuperimposed upon the translating apparatus to correspondingly affectthe audible output, tones from the speaker.

With such an arrangement, then, the feedback currents contain all thecomponent frequencies for setting up resonant vibrations not only in theoctave-related reeds but also in those reeds having vibration partialfrequencies of 1, 2, 3, 4 etc., or 4 etc., times the frequency of theexcited reed. Furthermore, the broad, continuous band of frequencies ofthe vibratile pick-up-support plate provides innumerable otherintervening frequencies corresponding to the roar of intermingled tonesheard from a tensioned-string piano when played with the loud pedaldepressed. Still further, the feedback-forced vibrations of the plate 40will set up vibrations of the remaining, non-resonant reeds since suchplate tends to vibrate, angularly, the fixed ends of all the reeds.

It is evident from the foregoing disclosure that the formant efiectscharacteristic of any type of soundboard instrument may be simulated. Inelectronic sustained-tone instruments, such as organs and the like, itis customary to use electrical formant circuits in an effort to simulatevarious conventional sustained-tone instruments of the direct acoustictype. Such circuits may also be used with my reed type mechanicalvibrator instruments of damped or sustained tone type. It may here beobserved that these prior electrical formant systems, having no directcoupling with the tone generating means and particularly no suchcoupling which varies note by note through the pitch range according tothe formant frequency characteristics of conventional instruments, canonly be efiective in the =10 particular pitch range for which theyfunction. Such pitch range is only of a length of two or three octavesin the musical scale.

My direct mechanically-coupled electromechanical formant system can beso tuned and damped over its longitudinal dimension along the reed scaleso as to secure any desired formant frequency effects in any or allparts of a scale having any desired pitch compass, or at least to apractical extent within the limitations imposed by the human ear.

While I prefer to make the vibratile plate, which supports the pick-ups,of magnetic material, the invention is not so limited. Reference is nowmade to Figure 7 wherein the pick-up supporting plate 40 is made ofnonmagnetic material such as, for example, aluminum. Vibration of theplate is brought about by a plurality of soft-iron rivets 59, one suchrivet spaced from each of the polarized cores 50.

In the Figures 3-7 embodiments of the invention the pick-ups comprisefiat, metallic plates secured to individual posts of insulatingmaterial. A preferred form of pick-up and mounting arrangement, from thestandpoint of facility of assembly and adjustment, is shown in Figures 8and 9. Here the individual pick-ups comprise a substantially U-shapedmember 60 having offset ends 6|, 62 lying in planes parallel to that ofthe reeds H], II, H2. The pick-up 60 is secured to an insulator bushing63 by means of a screw 64 which passes through a clearance hole in thebushing into a threaded hole in the base of the pick-up. The bushing 63passes through a hole in the plate 46 and is secured thereto by asuitable nut 65. Thus, the pick-ups are insulated from the plate 40 andcan be connected into the circuit by means of leads soldered toterminals disposed under the heads of the screws 64. It will be notedthat a single pick-up is associated with two reeds and a slight amountof adjustment between the pick-up ends 6|, 62 and the reeds can beaccomplished by appropriately bending the body and ends of each pick-up.The transverse center line passing through the alined ends of thepick-ups (such as the section line BB of Figure 8) coincides with thenodal points for the vibration partial H of the reeds, for purposesalready explained.

Figure 10 shows another construction of the individual pick-upsupporting post for use with a U-shaped pick-up of the type shown inFigures 8 and 9. Here the pick-up 60 is secured to an insulator bushing61 by the screw 64. The bushing 61 is provided with an external threadwhich cooperates with a threaded hole in the plate 40 whereby the planeof the pick-up ends 6|, 62 can be adjusted relative to the reeds H], II.The bushing 61 is then looked in position by the nuts 68, 69 which maybe made of metal and of a type such as those used for mountingconventional toggle switches.

Having now described several embodiments of my invention those skilledin this art will be able to make certain desired variations andmodifications in the individual components and their assembledrelationship without thereby departing from the spirit and scope of theinvention as set forth in the following claims.

I claim:

1. In an electronic musical instrument of the class comprising aplurality of tuned reeds carried by a reed rail, reed-vibrationtranslating pick-ups associated with the reeds and an electrical networkfor. translating relative vibrations aengzai between the: reedspick-upsinto electrical combination, To'f felectroniafinetic meansadapted. when .energized, to vibrate. the

reed. raiiandpickj-upa .andlfeedbackmeans enerkizin'ejthesaidielectroemagneticfmeans.from the Ictrica1...ritwork.

' IIn anjele'c'tronic. musicalfinstrument. of the class fcomp'rismgaplurality of tunedlreeds carried by .a reed frail, reed-vibrationtranslating piekeiips.associatedlwith'the reeds and an electrical'ntworkfor translatingrelative vibrations between the .reeds and pick up's intoelectrical waves.thelcombinationof a vibratile plate mechanicallvcoupled'tof the. reed rail and pick-ups,

'lecti'o'-magnetic' means adapted when energized "the eieemem net wdrk.

3.. 'Tl'ie'f invention as recited'in claim 2, wherein the 'saidvibratileplate. is made of magnetic material,

4. "The. inventionfas recited in" claim .2, wherein the said vibrati-leplate carries "magnetic material members.inagneticallylcoupled to thesaid eIectro-m'agnetic. means.

r 5. A musical instrument .comprisingaplurality of'tiinedreedscarried'by a' reed rail, avibratile plate secured to. .the. reedrail; reed-vibration pick=upsiassociated with. the reeds, said pick-upsbeing' carried by. and insulated from the said vibratilelplate; anelectrical network translating relative vibrations between. the reedsand pickups into electrical 'w'avesj 'an electro-acou'sticdeviceenergized, by th'elelectrical waves; .a nonvibratile"bas'e securedto the .vibratile p1ate,,said base havinga surface'spaced from thesaid.plate; electrof-magnetic means carried by said base and adapted. whenenergized, to vibrate the vibratile 'plate;. and a feedbackcircuit'connected between theelectrof-mag'netic device andthe saidelectiilcalfnetwork.

"6. 'Iheinvention as recited in claim 5,. include lug, a member.ofvi'sco-lelastic" material disposed betweenj'the said, platea'n'dba'se'.

"'7. .Amu'sical instrument of the. class employingan"eiectrical"networkf including an output .circuit havingian electroac'oustic device; .saidinstrue inentcoi'nprising .a'ree'd rail ;'f aplurality of .vibratory reed'secure'd to and. spaced alongthe reedrailpa vibratile plate secured .to the reed rail and 'spacejdl'trornjthereed's;* an ofiset end in the plate fin .the' regionqoflthe .reed rail;51,1101)? vibratile'basehavinga surface spaced" from the saidplate;ineans' securing the offset end .of the plate to "the 'base; insulatormembers secured 12 to. thesaid vvibratilaplate;lreedevibrationetranslatin'gi. means carriedby .the insulator members,

. said .translatinglmeansiorming .part. of \the electrical .network.electroiemagneticmeans carried by the non-vibratile base andadapted,;.,iipon energization, to vibrate the .vibratil'ebase; and

. means energizing said electro'em'agnetic means from the outputcircuitjof the.- instrument. 8. The invention as. recited inclaim'l,wherein the 'vibratile .plate-isimade of magnetic ,material and saidelectro-magneticmeans includes anl a'djustable, polarized core-having anand spaced from the saidiplate. j

9. Theinventlon as recited in claim'l, wherein the vibratile plateislmade .0: .nQn-magnetiQmaterial .and including .a niaiineticematerlalmen'1- ber. secured to. the said plate and in spacedaune ment with Isaid electro-m'agnetic means.

10. A musicalinstrument of the class employing an electrical network.including an output circuit having an ,electroeacoustic. device; saidinstrument. comprising a reed .rai1,".a plurality of vibratory reedssecured to and. spaced along the reed rail; a, vibrati-leplate securedto'.the...re'ed rail and spaced. fromthe reeds; anv offset end in the.plateinthe region ofthe reed rail; anon- -vibratiie .base 'havin'geasurface spaced from the .said plate; .means securing the offset endofthe plate to the base; a visco-elastic member disposed between the.said .base. and plate; insulator. in'emibers secured to the vibratileplate; capacity pick- Bmamm immssrma; .2

References (liter! an *the me or: this patent UNITED"'sTA'ijEs'ii'PAfrENTs

